| 摘要 |
PURPOSE:To enable optical signals which propagate through an optical circuit to be lessened in loss by a method wherein a part of a clad layer of a waveguide type active element is made conductive, another part of the clad layer of an optical waveguide is rendered semi-insulating, and a boundary plane between the conductive clad layer and the semi-insulating clad layer is formed to be tilted to a wave guiding direction. CONSTITUTION:A waveguide type phase modulator 20 as a waveguide type active element and a clad layer located at a traveling wave type amplifier 21 are selectively made electrically conductive, and on the other hand a clad layer 19 of an optical waveguide used for optical connection is rendered semi-insulating. As the clad layer 19 of the optical waveguide forming most of the overall length of an optical circuit is rendered semi-insulating, propagating optical signals are small in propagation loss. Selectively grown boundary planes between the conductive clad layer 18 of the waveguide type active element part and the semi-insulating clad layer 19 of the optical wave guide part are formed through a selective growth method to be tilted by angles of theta1 and theta2 to a direction vertical to the optical waveguide, whereby protuberances due to abnormal growth are lessened and optical connection of high efficiency can be realized. |
